The present invention relates to a method and an apparatus for making drill screws, and more particularly to a novel method and apparatus for repeatably making high performance drill screws.
The invention can be considered to be an improvement to a method and apparatus which is the subject of U.S. Pat. No. 3,280,412, wherein many of the fundamental techniques used in the present invention are described. The contents of U.S. Pat. No. 3,280,412 are incorporated herein by reference. The art of forming milled drill points on drill screws has generally involved a frame structure which carries a conveyor or turret which is adapted to convey successive screw blanks to various work stations. The screw blanks have elongated shanks exposed beneath the turret. It is upon these exposed blanks that various operations are performed. Methods and apparatus of the prior art generally utilize milling saws. Such methods and apparatus have been generally successful and have enabled commercially acceptable screws to be produced in an efficient manner.
The present invention involves a novel method and apparatus for milling drill points in screw blanks. Form relieved milling cutters are rotated at unusually high speeds to produce high performance screws at improved rates of production. The cutters can be adjusted in a simple manner to achieve variations in drill point geometry, and the speed of the cutters can be controlled to carefully maintain the quality of the products and maximize the life of the cutters.
It is an important object of the present invention to provide a method and apparatus for producing drilling screws with improved accuracy and improved production rates.
It is a further object of the present invention to provide a method and apparatus which allows the production of drill screws which have drilling tips with varying geometries.
A more specific object of the present invention is to provide an apparatus of the above described type having novel means for forming drill screws having curvilinear surfaces milled therein.
Other objects and advantages of the present invention will become apparent from the following description read in conjunction with the accompanying drawings.